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Another World Record Generalized Cullen Prime!

PrimeGrid - So, 17.03.2018 - 17:44
On 11 March 2018, 23:54:40 UTC, PrimeGrid’s Generalized Cullen/Woodall Prime Search found the largest known Generalized Cullen prime: 1806676*41^1806676+1 Generalized Cullen numbers are of the form: n*b^n+1. Generalized Cullen numbers that are prime are called Generalized Cullen primes. For more information, please see “Cullen prime” in The Prime Glossary. The prime is 2,913,785 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Cullen primes and 27th overall. Base 41 was one of 12 prime-less Generalized Cullen bases below b=121 that PrimeGrid is searching. The remaining bases are 13, 25, 29, 47, 49, 55, 69, 73, 101, 109 & 121. The discovery was made by Hiroyuki Okazaki (zunewantan) of Japan using an Intel(R) Xeon(R) E5-2670 CPU @ 2.60GHz with 4GB RAM, running Linux. This computer took about 7 hours and 13 minutes to complete the primality test using multithreaded LLR. Hiroyuki is a member of the Aggie The Pew team. The prime was verified on 12 March 2018 09:07:23 UTC by Scott Brown (Scott Brown) of the United States using an Intel(R) CPU @ 2.30GHz with 16GB RAM, running Windows 10 Professional Edition. This computer took about 15 hours 22 minutes to complete the primality test using LLR. Scott is also a member of the Aggie The Pew team. For more details, please see the official announcement.
Kategórie: Novinky z projektov

Year of the Dog Challenge starts March 16th 2018 18:00 UTC

PrimeGrid - Pi, 16.03.2018 - 13:08
To celebrate the start of Chinese new year, PrimeGrid is hosting a 7 day challenge from March 16th 2018, 18:00 UTC until March 23rd, 18:00 UTC. Work units from the 321 (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score. For more information, questions and chit chat concerning this challenge, please join us in this thread. And as always we hope to see you there and feel free to spread the word.
Kategórie: Novinky z projektov

Testing Some New Plan Classes

Milkyway@Home - Št, 08.03.2018 - 20:06
Hey Everyone,

I am going to try changing the GPU plan classes to reduce workunits sent to users without double precision gpus. If you notice any issues on your end, please let me know.


Kategórie: Novinky z projektov

Removing Hosts With High Error Counts

Milkyway@Home - St, 07.03.2018 - 21:55
Hey Everyone,

I am going to be issuing suspensions to 8 hosts with extremely high error counts (over 1000 in their recent history). If you own one of these hosts and are unhappy with the suspension, please message me and we can discuss removing the suspension.

This is a temporary solution until I can implement a more automated suspension system with occasional retesting of hosts to see if they have been fixed.

Any discussion about how to best implement an automated algorithm can go here and I will attempt to keep up.



I added a feature to determine if one of your hosts is suspended at a quick glance. Any of your suspended hosts will show up highlighted in red on the "computers on this account" page in your account information page. These hosts will not show up as red to anyone else and only you will know if you are suspended.
Kategórie: Novinky z projektov

Microbiome Immunity Project Already Extending the Known Universe of Protein Structures

World Community Grid - St, 07.03.2018 - 21:08
The Microbiome Immunity Project is off to a great start on predicting the structures of hundreds of thousands of bacterial proteins within the human gut. Read about their progress and their plans in their first project update.
Kategórie: Novinky z projektov

Reverting Change to Remove Unreliable Hosts

Milkyway@Home - Po, 05.03.2018 - 22:15
Hey Everyone,

I am going to be reverting the change to use the built in BOINC use reliable hosts option. It seems to be having unintended consequences to the usability of the project for some users.

In the future, Sidd and I will look into manually removing the worst offenders who are sending back erroring workunits.

For anyone effected, I apologize if you haven't been able to crunch for us recently.

Kategórie: Novinky z projektov

Scheduled Server Maintenance 3/5

Milkyway@Home - Po, 05.03.2018 - 17:18
Hey everyone,

We will be temporarily taking the server offline today (3/5) at 1pm to do some further hardware upgrades. This time we are adding a second CPU to the server allow more simultaneous connections.

This maintenance period will likely take longer than the last one as CPUs take longer to install and test.

If you have any questions, please let me know.


Server maintenance is concluded for today. We ended up not being able to complete the upgrade, so we are postponing it for a a week or so.
Kategórie: Novinky z projektov

Thanks for supporting SixTrack at LHC@Home and updates

LHC@home - Ut, 23.01.2018 - 19:08
Dear volunteers,

All members of the SixTrack team would like to thank each of you for supporting our project at LHC@Home. The last weeks saw a significant increase in work load, and your constant help did not pause even during the Christmas holidays, which is something that we really appreciate!

As you know, we are interested in simulating the dynamics of the beam in ultra-relativistic storage rings, like the LHC. As in other fields of physics, the dynamics is complex, and it can be decomposed into a linear and a non-linear part. The former allows the expected performance of the machine to be at reach, whereas the latter might dramatically affect the stability of the circulating beam. While the former can be analysed with the computing power of a laptop, the latter requires BOINC, and hence you! In fact, we perform very large scans of parameter spaces to see how non-linearities affect the motion of beam particles in different regions of the beam phase space and for different values of key machine parameters. Our main observable is the dynamic aperture (DA), i.e. the boundary between stable, i.e. bounded, and unstable, i.e., unbounded, motion of particles.

The studies mainly target the LHC and its upgrade in luminosity, the so-called HL-LHC. Thanks to this new accelerator, by ~2035, the LHC will be able to deliver to experiments x10 more data than what is foreseen in the first 10/15y of operation of LHC in a comparable time. We are in full swing in designing the upgraded machine, and the present operation of the LHC is a unique occasion to benchmark our models and simulation results. The deep knowledge of the DA of the LHC is essential to properly tune the working point of the HL-LHC.

If you have crunched simulations named "workspace1_hl13_collision_scan_*" (Frederik), then you have helped us in mapping the effects of unavoidable magnetic errors expected from the new hardware of the HL-LHC on dynamic aperture, and identify the best working point of the machine and correction strategies. Tasks named like "w2_hllhc10_sqz700_Qinj_chr20_w2*" (Yuri) focus the attention onto the magnets responsible for squeezing the beams before colliding them; due to their prominent role, these magnets, very few in number, have such a big impact on the non-linear dynamics that the knobs controlling the linear part of the machine can offer relevant remedial strategies.

Many recent tasks are aimed at relating the beam lifetime to the dynamic aperture. The beam lifetime is a measured quantity that tells us how long the beams are going to stay in the machine, based on the current rate of losses. A theoretical model relating beam lifetime and dynamic aperture was developed; a large simulation campaign has started, to benchmark the model against plenty of measurements taken with the LHC in the past three years. One set of studies, named "w16_ats2017_b2_qp_0_ats2017_b2_QP_0_IOCT_0" (Pascal), considers as main source of non-linearities the unavoidable multipolar errors of the magnets, whereas tasks named as "LHC_2015*" (Javier) take into account the parasitic encounters nearby the collision points, i.e. the so called "long-range beam-beam effects".

One of our users (Ewen) is carrying out two studies thanks to your help. In 2017 DA was directly measured for the first time in the LHC at top energy, and nonlinear magnets on either side of ATLAS and CMS experiments were used to vary the DA. He wants to see how well the simulated DA compares to these measurements. The second study seeks to look systematically at how the time dependence of DA in simulation depends on the strength of linear transverse coupling, and the way it is generated in the machine. In fact, some previous simulations and measurements at injection energy have indicated that linear coupling between the horizontal and vertical planes can have a large impact on how the dynamic aperture evolves over time.

In all this, your help is fundamental, since you let us carry out the simulations and studies we are interested in, running the tasks we submit to BOINC. Hence, the warmest "thank you" to you all!
Happy crunching to everyone, and stay tuned!

Alessio and Massimo, for the LHC SixTrack team.
Kategórie: Novinky z projektov

LHC@home down-time due to system updates

LHC@home - Ut, 23.01.2018 - 11:19
Tomorrow Wednesday 24/1, the LHC@home servers will be unavailable for a short period while our storage backend is taken down for a system update.

Today, Tuesday 23/1, some of the Condor servers that handle CMS, LHCb and Theory tasks will be down for a while. Regarding the on-going issues with upload of files, please refer to this thread.

Thanks for your understanding and happy crunching!
Kategórie: Novinky z projektov
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